On page 4, there is an "IDE Power" connector. It looks a lot like a 4 pin CPU fan connector, but it (obviously) provides different voltages that are appropriate for 3.5" IDE drives (5V, 12V) and ...

The existing Smart Connector uses a three-pin connector, while MagSafe on the Mac uses a five-pin connector. This is yet another wrinkle in Macotakara’s claim that these will be four-pin connectors.